just further to what I wrote, I see that I said 'without an interface' in my first post - an iMic is an interface so I might have been a little misleading. I'm not familiar with the ports on your Mac ....but I'm think it should work. Questions to tick of would be:
- have you had any luck with anything other than the Griffin G-cable?
- are you enabling the track (ie., the 'R' should be illuminted red to hear the signal)
-if you can't hear anything, can you see a signal is getting through, does the meter flicker?
- have you tried MIDI? (that's something to verify that Logic is working)
I had a lot of fun/luck with the iMic ...if you don't have one, its worth consdering. And they are good, and cheap (compared to the interface aailable), and mine still works well after years of use.